The invention relates to the lighting arts. It is especially applicable to providing substantially uniform rectangular flood lighting of vertical walls or other flat vertical structures, and will be described with particular reference thereto. However, the invention is not limited thereto, and will also find application in other flood lighting tasks, such as the illumination of non-flat vertical objects, perimeter illumination of outdoor surfaces such as parking lots, football fields, and the like, and uniform illumination of indoor flooring using wall-mounted flood lights.
Flood lighting is typically used in parking lots, athletic fields, and other areas to provide illumination for convenience and safety. Similarly, architectural features such as building walls are advantageously uniformly illuminated at night. Flood lighting is designed to illuminate large areas, preferably with relatively uniform illumination across the area. To appropriately distribute the light output, the electric lamps that produce the light are typically coupled with a reflector. The reflector geometry for transforming the essentially point light source distribution of a conventional incandescent lamp, halogen lamp, or metal halide lamp into a wide-area, spatially uniform flood light illumination is typically rather complex. This is particularly the case for asymmetric flood lighting in which the flood light is not located symmetrically directly above the surface to be illuminated, but rather is located at a side, such cases arising for example in lighting parking lots from the perimeter, lighting athletic fields from the sidelines, lighting tall buildings from flood lights positioned relatively near ground level, and the like. Additionally, in such situations a substantially rectangular illumination of a substantially flat surface is typically desired, which further complicates the geometric requirements of the flood light reflector.
In the past, these complex geometric requirements have been met using multi-faceted segmented reflectors. These reflectors are assembled from multiple strips of pre-finished reflective metal, sometimes having various finishes. Segmented reflectors are relatively simple to manufacture since the required shaping can be accomplished using conventional and low cost sheet metal shaping techniques. However, these prior art reflectors have several disadvantages. They require labor-intensive assembly of the multiple parts, either at the factory or in the field, e.g. by the customer. The multiple-component fabrication introduces potential failure mechanisms at the interconnections. The multiple segments can have various types of surface finishes and segment interconnections of varying optical quality, producing lighting non-uniformities and other optical degradation.
Single-piece reflectors, which are typically machine-pressed from a single sheet of aluminum or other metal blank, are also known. U.S. Pat. No. 5,816,694, which has the same assignee as the present invention and is incorporated by reference herein, discloses a hydroformed symmetrical flood light reflector that produces a square light distribution. However, because of their more complex reflection geometry, asymmetrical flood light reflectors have in the past been produced in multi-segmented fashion rather than as single-piece reflectors.
The present invention contemplates an improved reflector that overcomes the above-mentioned limitations and others.
In accordance with one embodiment of the present invention, an asymmetric flood light reflector is disclosed. A hydroformed. continuous metal form defines a lamp space that is adapted to receive an associated lamp. The metal form has a forward opening for outputting light generated by the associated lamp. The metal form further includes a rear reflector section arranged rearward of the lamp space and adapted to reflect backward-directed lamp illumination forward in a crossing pattern, a forward reflector section disposed forward of the rear reflector section and adapted to reflect lamp illumination forward in a crossing pattern, and a plurality of planar surfaces that connect the forward and rear reflector sections. The hydroformed continuous metal form is adapted to cooperate with the associated lamp to produce a substantially rectangular area of substantially uniform illumination that is asymmetrically disposed relative to the reflector.
In accordance with another embodiment of the present invention, a flood light is disclosed, including a light source and an asymmetric reflector. The asymmetric reflector comprises a single, continuous, reflective metal sheet that is formed to include a plurality of reflective sub-surfaces. The reflector cooperates with the light source to produce uniform lighting over a rectangular area located asymmetrically relative to the flood light.
In accordance with yet another embodiment of the present invention, a method is disclosed for flood lighting a rectangular area in a substantially uniform manner. Light is generated at a spatial point asymmetrically located relative to the rectangular area. The generated light is reflected onto the rectangular area using a single metal sheet that has a pre-selected deformation shape adapted to reflect the generated light into the rectangular area with varying light intensity to provide substantially uniform illumination throughout the rectangular area.
In accordance with still yet another embodiment of the present invention, an apparatus for manufacturing an asymmetric flood light reflector is disclosed. The apparatus includes a punch element that is adapted for use with a hydroform press. The punch element conforms with the inner surface of an asymmetric flood light reflector.
Numerous advantages and benefits of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description.